Keep your cheese from hardening

Have you ever gone to pull out some cheese only to find that some of it has hardened? I love a good cheese platter with lots of fruits and vegetables. Most of the time the entire platter gets devoured, but on those rare occasions when I have cheese left over I do not want it to harden on the edges before I can use it, so before putting it in the refrigerator I butter the exposed edges which keeps it soft.